(19)

(11)

EP 1 121 709 A1

(12)

(43) Date of publication: 08.08.2001 Bulletin 2001/32 (21) Application number: 99951513.3 (22) Date of filing: 13.10.1999

(51) International Patent Classification (IPC)7: H01J 49/42, H01J 49/38, H01J 49/02 (86) International application number: PCT/US9921/630 (87) International publication number: WO 0024/036 (27.04.2000 Gazette 2000/17)

(84) Designated Contracting States: AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE (30) Priority: 16.10.1998 US 173855 (71) Applicant: Siemens Applied Automation, Inc. Bartlesville, OK 74005 (US)	(72) Inventors: LITTLEJOHN, Duane, P. Manlius, NY 13104 (US) ARNOLD, Robert, W. Johnson City, NY 13790 (US) (74) Representative: Neill, Andrew Peter  Siemens Shared Services Limited,IPD,Siemens House,Oldbury Bracknell,Berkshire RG12 8FZ Bracknell,Berkshire RG12 8FZ (GB)